The Mustang and Focus are two very different cars; they are the best of both ends of the spectrum. The people who want those types of cars are all in the middle of the spectrum.

I know I can count on you to imagine a poor outcome. Someone that wants a Mustang will buy one and the same for the Focus. Look at it this way, the competition for an RS are really cars like the Subaru WRX and Lancer Evolution not the Mustang. One factor in favor of the RS coming here is that the Wayne Michigan assembly plant is already up for years assembling the Focus (and Focus ST, Electric and the two C-Maxes) and it's humming along very nicely, building fine cars. Adding a Focus RS that is produced in relatively low numbers shouldn't be a problem.